San Diego Region - Bacteria Impaired Waters TMDL Project II for San Diego Bay and Dana Point Harbor Shorelines

TMDLs Adopted June 11, 2008

On June 11, 2008, the Regional Board adopted a Basin Plan amendment to incorporate the TMDLs developed for Baby Beach in Dana Point Harbor and Shelter Island Shoreline Park in San Diego Bay. This action meets requirements of section 303(d) of the Clean Water Act. The Basin Plan amendment process is authorized under section 13240 of the Water Code. The Basin Plan amendment is a project subject to the California Environmental Quality Act (CEQA) and the San Diego Water Board is the lead agency.

Background

Fecal bacteria originate from the intestinal flora of warm-blooded animals, and their presence in surface water is used as an indicator of human pathogens. Pathogens can cause illness in recreational water users. Bacteria have been historically used as indicators of human pathogens because they are much easier and less costly to measure than the pathogens themselves.

The Clean Water Act requires states to identify those waters within its boundaries for which the effluent limitations are not stringent enough to implement any water quality standards (WQS) applicable to such waters. The Clean Water Act also requires states to establish Total Maximum Daily Loads (TMDLs) for such waters. The purpose of a TMDL is to attain water quality objectives (WQOs) and restore and protect the beneficial uses of an impaired waterbody. TMDLs represent a strategy for meeting WQOs by allocating quantitative limits for point and nonpoint pollution sources. A TMDL is defined as the sum of the individual waste load allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources and natural background such that the capacity of the waterbody to assimilate pollutant loading (i.e., the loading capacity) is not exceeded.

The San Diego Water Board developed and adopted TMDLs for 19 beaches and creeks in the San Diego Region as part of Bacteria Impaired Waters TMDL Project I. This TMDL's address the impaired shoreline segments in Dana Point Harbor and San Diego Bay.

Total Maximum Daily Loads for Indicator Bacteria for San Diego Bay and Dana Point Harbor Shorelines

In 2004, Bacteria Impaired Waters TMDL Project II included six bacteria impaired shorelines in Dana Point Harbor and San Diego Bay: Baby Beach in Dana Point Harbor and Shelter Island Shoreline Park, B Street Pier, G Street Pier, Tidelands Park, and Chula Vista Marina in San Diego Bay. Only Baby Beach in Dana Point Harbor and Shelter Island Shoreline Park in San Diego Bay were confirmed as still impaired by indicator bacteria. Therefore, TMDLs were only developed for these two shoreline segments.

Adopted Resolution No. R9-2008-0027 and Basin Plan amendment and the Final Technical Report and Appendices are available in the Public Documents section below.

Contact Information

Any questions or comments regarding these TMDLs may be sent to Mr. Wayne Chiu, Water Resource Control Engineer, at 858 637-5558, or email at WChiu@waterboards.ca.gov.

Public Documents

Resolution No. R9-2008-0027 and Basin Plan Amendment (dated June 11, 2008)

Final Technical Report (dated June 11, 2008)

Appendices

• Appendix A - Water Quality Objectives for Indicator Bacteria
• Appendix B - Peer Review Comments and Responses
• Appendix C - Tentative Resolution No. R9-2008-0027 and Basin Plan Amendment
• Appendix D - Data Sources
• Appendix E - Review of Shoreline Bacteria Data
• Appendix F - Wet Weather and Dry Weather Configuration, Calibration, and Validation
• Appendix G - Assumptions for Model Development and TMDL Calculations
• Appendix H - Existing and Reduced Concentrations - Wet Weather
• Appendix I - EFDC Calibration and Modeling Results
• Appendix J - Maps of Watersheds for Shoreline Segments
• Appendix K - Load Reduction Analyses
• Appendix L - Dry Weather Modeling Load Estimates
• Appendix M - Environmental Analysis and Checklist
• Appendix N – Responses to Public Comments